This invention relates to a switching device equipped with a variable resistor and more particularly to a switching device for making or breaking the contacts and operating the variable resistor by means of one and the same operating knob.
A switching device of the sort above mentioned has normally employed a rotatively operating variable resistor, whose operating shaft is made movable in the axial direction with its front end being projected from the body of the variable resistor and used to turn on or off the switching device.
However, a linearly operating variable resistor in place of the rotatively operating variable resistor is sometimes held important for use in equipment. The reason for this is that only a look at the operating knob position makes it possible to readily confirm a set value, i.e., the linearly operating variable resistor is handy to use because its operating knob can provide a relatively large moving stroke. Accordingly, there has been called for the introduction of a switching device equipped with a variable resistor in the form of a combination of a linearly operating variable resistor and a switch mechanism.
Even if it is attempted to adopt the switch mechanism in the above rotatively operating variable resistor in the hope of providing the linearly operating variable resistor with switch functions, the fact that the operating knob has a large moving stroke in view of its mechanical properties still makes such an attempt futile. Actually, no switching device with a variable resistor in the form of the combination of the linearly operating variable resistor and the switch mechanism has yet been introduced.